Topological edge states of the dissipative AB chain are characterized by the non-Bloch band theory [1]}, [2]}. The idea is to take into account the deformation of the bulk eigenstates under the non-Hermitian skin effect, replacing the phase factor \(e^{ik}\)  of the Bloch waves (under the periodic boundary condition) with a spatial mode factor \(\beta (k)=|\beta (k)|e^{ik}\) . Here the quasimomentum \(k\in [0,2\pi )\) , and the trajectory of \(\beta (k)\)  on the complex plane is known as the generalized Brillouin zone (GBZ), which can be calculated from the Schrödinger's equation as shown below.
